Acid-base treatment

H. A. Nasr-El-Din, J. D. Lynn, and K. C. Taylor. Lab testing and field application of a large-scale acetic acid-based treatment in a newly developed carbonate reservoir. In Proceedings Volume. SPE Oilfield Chem Int Symp (Houston, TX, 2/13-2/16), 2001. 

Importantly, knowledge of intestinal bile acid transport and metabolism, coupled with increased understanding of the mechanistic basis of the pro-tumorigenic activity of bile acids against CRC cells in vitro, has recently led to development and testing of bile acid-based treatment and prevention strategies for sporadic and inflammatory bowel-disease-associated CRC. Existing evidence that manipulation of the luminal secondary bile acid pool and/or therapy with ursodeoxycholic acid (UDCA) may have promise for prevention of CRC will be assessed. 

Analysis by XPS after incorporation of the linear or dendritic cationic polymers showed an increase in the atom % N consistent with incorporation of an N-rich polycation. The polyvalent interactions between the cationic polyelectrolytes and the poly(sodium acrylate)graftson PE were stable to Soxhlet extraction with 95% ethanol, repeated acid/base treatment, and soaking or sonication in isopropanol and THE However, in these cases, simple acid treatment did not release the cationic polymer as was the case with PAA/Au grafts even though grafting in both cases was reportedly ionic and not covalent. 

Oxides of Ba and Sr are soluble in acidic and neutral aqueous solutions, and as seen from Fig. 17.1, like MgO, their solubility decreases as the pH increases on the alkahne side. Therefore, these two oxides may be easily stabilized in CBPC using the acid-base treatment. 

Furthermore, formation of an unstable isopropylcobalt complex intermediate in the dehydrogenation step (Reaction 10) cannot be ruled out since evidence for the formation of small quantities of such a complex has been obtained in these reactions (acid-base treatment (23) yields isobutyronitrile). This type of disproportionation resembles that... 

In summary, depending on the nature of sources and conditions, the radiation effects of the CNTs in a relatively short period of time were very different. 1) The effective surface oxidation was observed for the samples exposed to the proton for 15 min and UV-ozone environment in 60 min, and the oxidative functional groups produced by proton and UV-ozone were essentially similar to those produced by acid-based treatment.[31] 2) The electron radiation could remove the carbon impurities, when the operating conditions are carefully optimized. Nevertheless, these radiation methods described above were performed in a form of a dried CNT powder, thus did not produce any harmful chemical byproducts. 

The increase in the intrinsic oxidation state of EM base after one cycle of acid-base treatment is observed only in film samples. Similar treatment does not result in a significant increase in the intrinsic oxidation. state of EM powders [86]. Thus, sample morphologies play an important role during protonation-deprotonation in aqueous media. Each particle of EM powder is an aggregate of many small granules [87], while atomic force microscopic (AFM) study of EM films cast from NMP reveals featureless and dense surface nanostructures before and after protonation [88]. The difference in behaviour between EM film and powder towards protonation—de-protonation and the changes in the intrinsic oxidation states of EM films as a funetion of aeid exposure time during aeid-base treatment are thus attributable to the hindranee to water diffusion and the assoeiated hydrolysis reaetion [89] in the dense EM films. An earlier study [84] has also shown that... 

Table 3.2. Changes in intrinsic redox states of EM base Alms after one cycle of acid-base treatment. (Reprinted with permission from ref 85, Elsevier Sci. S.A.)...

EM base films cast from NMP solutions may exhibit changes in the intrinsic oxidation state when undergoing a protonation de-protonation cycle [85,86]. For protonation carried out in aqueous mineral acids, an acid treatment time of one hour followed by rapid deprotonation in NaOH, can increase the intrinsic oxidation state to that of NA. However, lower oxidation. states than that of NA were obtained from films with increasing acid exposure time. The increase in intrinsic state after one cycle of acid-base treatment is not readily observed in EM powders [85,86]. The difference in behaviour many be due to the hindrance to water diffusion and the associated hydrolysis reactions in the dense as-cast EM base films. PAN salt films obtained either by acid treatment of as-cast EM base film or by direct casting of PAN salts in NMP solutions also undergo a change in film morphology upon deprotonation [327]. As-cast EM base films lack porosity... 

Eurukawa and co-workers [81] state that PANI is an interesting material because it is not only an ECP but is also a good material to use as an electrode of a secondary battery with aqueous or non-aqueous electrolytes. PANI polymerised from aniline in an aqueous acid solution is converted to several forms with different electrical properties by acid/base treatments and oxidation/reduction. The as-polymerised form gives high electrical conductivity ( 5 S/cm). It becomes insulating when treated with an aqueous alkaline solution or is reduced electrochemically in an aqneons acid solution. Reduced-alkali-treated PANI is also insulating and is unstable in air its colour changes from white to blue upon exposure to air. PANI doped with electrolyte anions is obtained by electrochemical oxidation [82]. It was found in this work to be a new conductivity form (o = 5.8 S/cm). Recently, a secondary lithium battery with a reduced alkali pellet as the cathode, and non-aqueous electrolytes has been developed as a power source of memory back up and a maintenance-free power source combined with a solar battery. 

In the present article, the size and the loading efficiency of metal particles were investigated by changing the preparation method of carbon-supported platinum catalysts. First, the effect of acid/base treatment on carbon blacks supports on the preparation and electroactivity of platinum catalysts. Secondly, binary carbon-supported platinum (Pt) nanoparticles were prepared using two types of carbon materials such as carbon blacks (CBs) and graphite nanofibers (GNFs) to check the influence of carbon supports on the electroactivity of catalyst electrodes. Lastly, plasma treatment or oxyfluorination treatment effects of carbon supports on the nano structure as well as the electroactivity of the carbon supported platinum catalysts for DMFCs were studied. 

Acid/Base Treatments of Carbon Blacks Supports... 

Immediately after the deposition (before acid/base treatment) the samples were studied in different conditions. The neutron reflectivity curves are summarized in Fig. 2. The swefling and water uptake in the samples and their reversibility were followed by exposing the samples subsequently to liquid D2O, dry N2, and D2O saturated vapors and again to liquid D2O. Detailed analysis of the obtained results was possible after fitting the data and converting... 

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